U.S. patent number 7,053,393 [Application Number 10/454,320] was granted by the patent office on 2006-05-30 for alignment apparatus for object on stage.
This patent grant is currently assigned to Olympus Corporation. Invention is credited to Shunsuke Kurata, Yoshihisa Taniguchi.
United States Patent |
7,053,393 |
Taniguchi , et al. |
May 30, 2006 |
Alignment apparatus for object on stage
Abstract
An object is held on a stage of an equipment, the stage is
rotated in order to acquire a detection signal corresponding to a
position of an outer peripheral edge of the object, a displacement
of the object with respect to an alignment reference position is
obtained based on this detection signal, and the stage is subjected
to movement control so as to eliminate this displacement, thereby
aligning the object.
Inventors: |
Taniguchi; Yoshihisa (Okaya,
JP), Kurata; Shunsuke (Kamiina-gun, JP) |
Assignee: |
Olympus Corporation (Tokyo,
JP)
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Family
ID: |
29561696 |
Appl.
No.: |
10/454,320 |
Filed: |
June 4, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20030222229 A1 |
Dec 4, 2003 |
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Foreign Application Priority Data
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Jun 4, 2002 [JP] |
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2002-163263 |
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Current U.S.
Class: |
250/559.3;
250/559.4 |
Current CPC
Class: |
G01N
21/9501 (20130101) |
Current International
Class: |
G01N
21/86 (20060101) |
Field of
Search: |
;250/559.3,559.33,559.36,548,221,559.4 ;356/399,400,401
;414/935,936 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Le; Que T.
Assistant Examiner: Lu; Tony
Attorney, Agent or Firm: Scully, Scott, Murphy &
Presser, P.C.
Claims
What is claimed is:
1. An alignment apparatus comprising: a stage which is provided in
an inspection equipment which performs inspection with respect to
an object, and also functions as a stage of the inspection
equipment, holds the object delivered by a carriage robot, and
carries out a movement operation with respect to the object in a
direction XY and a rotation operation in a rotational direction; a
sensor which detects an outer peripheral edge of the object
rotating by the rotation operation of the stage; and an alignment
control portion which obtains a central position and an arrangement
direction of the object based on positional information of the
outer peripheral edge detected by the sensor, acquires a
displacement quantity of the central position of the object from an
alignment reference position and a displacement quantity in the
arrangement direction, and controls to drive the stage in the
direction XY and the rotational direction in accordance with the
displacement quantities; wherein the inspection equipment inspects
with respect to the object on the stage.
2. The alignment apparatus according to claim 1, wherein the stage
has: a holding stage which holds the object; and an XY stage which
moves the holding stage in respective directions orthogonal to each
other.
3. The alignment apparatus according to claim 2, wherein the
holding stage has: a rotary stage which is provided on an inner
periphery so as to be capable of moving up and down and can rotate
while sucking and holding the object; and a suction holding stage
which is provided on an outer periphery of the rotary stage, and
sucks and holds the entire surface of the object.
4. The alignment apparatus according to claim 2, wherein the
holding stage forms a notch portion and a hole portion used to
detect an outer peripheral edge according to a size of the object
by using the sensor.
5. The alignment apparatus according to claim 1, wherein the sensor
has: a light projecting element which projects the light; and a
light receiving element which outputs a signal on a level
corresponding to a light quantity of the light which is projected
from the light projecting element and incident thereupon without
being blocked by the outer peripheral edge of the object.
6. The alignment apparatus according to claim 1, wherein a
plurality of the sensors are provided in accordance with a size of
the object.
7. The alignment apparatus according to claim 1, wherein the stage
has a holding stage which rotatably holds the object and an XY
stage which moves the holding stage in respective directions
orthogonal to each other, and the sensor is provided on the XY
stage and detects the outer peripheral edge of the object which
rotates by the holding stage.
8. The alignment apparatus according to claim 7, wherein the stage
can move between a delivery position for the object and a
predetermined position where the inspection is carried out in the
equipment, and the sensor detects the outer peripheral edge of the
object in a period after the stage receives the object at the
delivery position until it moves to the predetermined position.
9. The alignment apparatus according to claim 1, further comprising
a buffer holding portion which is provided on a carriage path of
the object between the carriage robot and the stage and holds a
plurality of the objects.
10. The alignment apparatus according to claim 9, wherein the
buffer holding portion is a swiveling arm having at least two
carnage arms.
11. The alignment apparatus according to claim 9, wherein the
buffer holding portion is a swiveling arm having a rotary shaft and
three carriage arms provided with respect to the rotary shaft at
equal angles.
12. The alignment apparatus according to claim 11, wherein the
swiveling arm moves each of the carriage arms to circulate to an
object delivery position, a macro inspection position, and a micro
inspection delivery position.
13. The alignment apparatus according to claim 1, wherein the
inspection equipment is an inspection apparatus for a semiconductor
wafer.
14. The alignment apparatus according to claim 1, wherein the
object is a semiconductor wafer.
15. An alignment apparatus comprising: an XY.theta. stage which is
provided to a wafer inspection apparatus which performs a micro
inspection for a semiconductor wafer, and also functions as a stage
of the micro inspection and holds the semiconductor wafer delivered
by a carriage robot by full suction, and performs a movement
operation for the semiconductor wafer in a direction XY and a
rotation operation in a direction .theta., the XY.theta. stage
forming a notch portion and a hole portion at positions
corresponding to each wafer edge according to a size of the
semiconductor wafer; a swiveling arm which is provided on a
carriage path of the semiconductor wafer between the carriage robot
and the XY.theta. stage and has three carriage arms which hold
three of the respective semiconductor wafers, the swiveling arm
moving each of the carriage arms to circulate to a delivery
position of the semiconductor wafer, a macro inspection position
and a micro inspection delivery position; respective sensors
provided at respective positions corresponding to the notch portion
and the hole portion and detect a wafer edge of the semiconductor
wafer rotating by the rotation operation of the XY.theta. stage,
each of the sensors having a light projecting element which
projects the light and a light receiving element which outputs a
signal on a level corresponding to a quantity of the light incident
thereupon without being blocked by the wafer edge of the
semiconductor wafer; and an alignment control portion which obtains
a central position displacement of the semiconductor wafer with
respect to an alignment reference position and a displacement
quantity in a direction of a notch or an original flat of the
semiconductor wafer based on positional information of the wafer
edge of the semiconductor wafer detected by any one of the
respective sensors, and at the time of micro inspection controls to
move the XY.theta. stage in the direction XY and the direction
.theta. so as to eliminate the central position displacement and
the displacement quantity in the direction of the notch or the
original flat, thereby aligning the semiconductor wafer to the
alignment reference position; wherein the wafer inspection
apparatus inspects the semiconductor wafer on the XY.theta. stage.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from the prior Japanese Patent Application No. 2002-163263, filed
Jun. 4, 2002, the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The Present invention relates to an alignment apparatus which
aligns a semiconductor wafer to a predetermined posture when taking
out an object such as a semiconductor wafer accommodated in a
storage container by a carriage robot and delivering it to an
equipment such as an inspection apparatus.
2. Description of the Related Art
As an alignment apparatus for a semiconductor wafer, there is a
technique disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication
No. 8-215876. In this publication, a semiconductor wafer is taken
out from a wafer carrier by a carriage robot and delivered to a
pre-alignment apparatus. The pre-alignment apparatus irradiates a
flat of the semiconductor wafer with a light beam and
photo-electrically converts a part of it, thereby detecting a
positional relationship between the flat and an axis X or Y in a
rotating direction. Thereafter, the pre-alignment apparatus
performs positioning of the semiconductor wafer in the rotating
direction based on the detected positional relationship between the
flat and the axis X or Y in the rotating direction. The positioned
semiconductor wafer is again taken out from the pre-alignment
apparatus by the carriage robot, and mounted on a stage of a
processing apparatus.
In the above-described publication, however, the pre-alignment
apparatus and the processing apparatus are separately provided.
Therefore, the semiconductor wafer must be carried from a wafer
carrier to the pre-alignment apparatus by the carriage robot, and
then carried from the pre-alignment apparatus to the processing
apparatus after positioning of the semiconductor wafer.
Accordingly, it takes a time to perform each carriage, and also
takes a time until the semiconductor wafer is processed.
In a manufacturing field of the semiconductor wafer, there are
requests to reduce a tact time of manufacturing/processing. Thus,
the time required for alignment of the semiconductor wafer should
be shortened.
Alternatively, since the semiconductor wafer is carried from the
pre-alignment apparatus to the processing apparatus by the carriage
robot after positioning of the semiconductor wafer, there is a
possibility that a deviance is generated in positioning of the
semiconductor wafer.
BRIEF SUMMARY OF THE INVENTION
According to a major aspect of the present invention, there is
provided an alignment apparatus comprising: a stage which is
provided to an equipment which performs processing or inspection
with respect to an object, holds the object delivered by a carriage
robot and effects a movement operation of the object in a direction
XY and a rotation operation in a rotating direction; a sensor which
detects an outer peripheral edge of the object rotating by the
rotation operation of the stage; and an alignment control portion
which obtains a displacement of the object relative to an alignment
reference position based on positional information of the outer
peripheral edge detected by the sensor, controls to move the stage
so as to eliminate this displacement and aligns the object to the
alignment reference position.
Advantages of the invention will be set forth in the description
which follows, and in part will be obvious from the description, or
may be learned by practice of the invention. Advantages of the
invention may be realized and obtained by means of the
instrumentalities and combinations particularly pointed out
hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The accompanying drawings, which are incorporated in and constitute
a part of the specification, illustrate embodiments of the
invention, and together with the general description given above
and the detailed description of the embodiments given below, serve
to explain the principles of the invention.
FIG. 1 is a block diagram showing a wafer inspection apparatus to
which an embodiment of an alignment apparatus according to the
present invention is applied;
FIG. 2 is a view showing a positional relationship between a light
projecting element and a light receiving element relative to a
semiconductor wafer having a diameter of 300 mm in the embodiment
of the alignment apparatus according to the present invention;
FIG. 3 is a view showing a positional relationship between a light
projecting element and a light receiving element relative to a
semiconductor wafer having a diameter of 200 mm in the embodiment
of the alignment apparatus according to the present invention;
FIG. 4 is a cross-sectional view of a rotary stage and suction
holding in the embodiment of the alignment apparatus according to
the present invention;
FIG. 5 is a view showing an example of a detection signal outputted
from a sensor in the embodiment of the alignment apparatus
according to the present invention; and
FIG. 6 is a view showing a modification of a sensor arrangement of
the alignment apparatus according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will now be
described hereinafter with reference to the accompanying
drawings.
FIG. 1 is a block diagram showing a wafer inspection apparatus to
which an alignment apparatus is applied. The wafer inspection
apparatus consists of a loader apparatus 1 and an inspection
apparatus 2. The loader apparatus 1 is constituted by wafer
carriers 3a and 3b and a carriage robot 4. The respective wafer
carriers 3a and 3b accommodate therein a plurality of semiconductor
wafers 5 in the vertical direction with a predetermined pitch. Of
the respective semiconductor wafers 5, the semiconductor wafer 5
which is yet to be inspected is accommodated in, e.g., the wafer
carrier 3a, and the inspected semiconductor wafer 5 is accommodated
in the wafer carrier 3b.
A carriage robot 4 takes out the uninspected semiconductor wafer 5
accommodated in the wafer carrier 3a, delivers it to the inspection
apparatus 2, receives the semiconductor wafer 5 which has been
already inspected by the inspection apparatus 2 and accommodates it
in the wafer carrier 3b.
The carriage robot 4 interlocks three connecting arms (which will
be referred to as articulated arms hereinafter) 6 to 8 and thereby
constitute articulated arms. A hand 9 is connected to the end side
of the articulated arms 6 to 8. A plurality of suction holes 9a are
provided to the hand 9. The hand 9 sucks and holds the
semiconductor wafer 5. The hand 9 moves forward or backward by
expansion and contraction operations of the articulated arms 6 to
8. The base side of the articulated arms 6 to 8 can rotate in a
direction indicated by an arrow A around an axial direction with
respect to a rotary shaft 10.
The carriage robot 4 is provided so as to be capable of moving in a
direction indicated by an arrow B by a movement mechanism 11.
The inspection apparatus 2 fetches an image of a surface of the
semiconductor wafer 5 enlarged by a microscope 61, and acquires a
type or a size of a defective part on the surface of the
semiconductor wafer 5.
A swiveling arm 20 and an XY.theta. stage 21 are provided on a
counter 22 of the inspection apparatus 2. The swiveling arm 20 is
provided on the left side seen from a front side F in the
inspection apparatus 2. The XY.theta. stage 21 is provided on the
right side seen from the front side F in the inspection apparatus
2.
A set position of the swiveling arm 20 is on a carriage path for
the semiconductor wafer 5 between the carriage robot 4 and the
XY.theta. stage 21. The swiveling arm 20 acts as a buffer holding
portion which holds a plurality of, e.g., two semiconductor wafers
5.
The swiveling arm 20 has a rotary shaft 23 and three carriage arms
24 to 26 provided at equal angles (e.g., 120 degrees) with respect
to the rotary shaft 23. A hand formed into a substantial L shape is
integrally provided at an end of each of the respective carriage
arms 24 to 26. A plurality of suction holes (wafer chucks) 27 are
formed to each of the carriage arms 24 to 26. Each suction hole 27
is connected to a suction apparatus such as a suction pump.
The swiveling arm 20 integrally moves up and down the three
carriage arms 24 to 26 by providing the rotary shaft 23 so as to be
capable of moving upwards and downwards.
The swiveling arm 20 rotates in, e.g., a counterclockwise direction
(direction indicated by an arrow H) in the drawing around the
rotary shaft 23. As a result, the three carriage arms 24 to 26
circulate at a wafer delivery position P.sub.1, a macro inspection
position P.sub.2 and a micro inspection delivery position
P.sub.3.
At the wafer delivery position P.sub.1, the semiconductor wafer 5
is delivered between the carriage robot 4 and the swiveling arm
20.
At the macro inspection position P.sub.2, the macro inspection is
carried out with respect to the semiconductor wafer 5. In the macro
inspection, the semiconductor wafer 5 is irradiated with the light,
the scattered light is observed, and irregularities in film, a
large defective position and others on the semiconductor wafer 5
are visually detected.
At the micro inspection delivery position P.sub.3, the
semiconductor wafer 5 is delivered between any one of the
respective carriage arms 24 to 26 and the XY.theta. stage 21.
The XY.theta. stage 21 consists of an X axis slider 30, an X axis
stage 31, a Y axis stage 32 and a holding stage 33. The X axis
stage 31 is provided so as to be capable of moving on the X axis
slider in the direction of the axis X. The Y axis stage 32 is
provided so as to be capable of moving on the X stage 31 in the
direction of the axis Y.
The holding stage 33 has a rotary stage 34 and a suction holding
stage 35. The rotary stage 34 is provided so as to be capable of
moving up and down and rotating. The rotary stage 34 sucks and
holds the semiconductor wafer 5.
The suction holding stage 35 is provided on the outer periphery of
the rotary stage 34, and formed into an annular shape (a so-called
a donut shape) in order to suck and hold the semiconductor wafer
5.
The rotary stage 34 and the suction holding stage 35 are provided
on a concentric circle. The rotary stage 34 is formed to, e.g.,
approximately .phi.80 mm, and the suction holding stage 35 is
formed to, e.g., approximately .phi.300 mm.
FIGS. 2 and 3 are block diagrams showing the XY.theta. stage 21
from the lateral direction. The suction holding stage 35 is
supported on the Y axis stage 32 through supports 36. The rotary
stage 34 is provided to a rotary shaft of a motor 37. The rotary
stage 34 and the motor 37 are integrally provided so as to be
capable of moving up and down.
FIG. 4 is a cross-sectional view showing the rotary stage 34 and
the suction holding stage 35. A bank 41 is formed on the outer
peripheral edge of the rotary stage 34. Respective banks 42 and 43
are formed on the outer peripheral edge and the inner peripheral
edge of the suction holding stage 35. The respective banks 41 to 43
are formed to have the same height.
Many pins 44 are formed on the bottom surface of the rotary stage
34. Many pins 45 are formed on the bottom surface of the suction
holding stage 35. The respective pins 44 and 45 are formed to have
the same height as that of the respective banks 41 to 43.
The bank 42 is formed into the same shape as the outer peripheral
shape of the semiconductor wafer 5 having a diameter of 300 mm in
order to suck and hold the semiconductor wafer 5 having the
diameter of 300 mm. The bank 42 and the bank 43 on the inner
peripheral edge form an annular full suction pad.
A circular convex portion 46 is formed between the respective banks
42 and 43 of the suction holding stage 35. The convex portion 46 is
formed into the same shape as the outer peripheral shape of the
semiconductor wafer 5 having the diameter of 200 mm in order to
suck and hold the semiconductor wafer 5 having the diameter of 200
mm. The convex portion 46 is also formed to have the same height as
the respective banks 42 and 43. The convex portion 46 and the bank
43 on the inner peripheral edge form an annular full suction
pad.
Many suction holes are formed on the rotary stage 34 and the
suction holding stage 35. Each suction hole communicates with the
suction apparatus.
At the time of inspection of the semiconductor wafer 5, when the
semiconductor wafer 5 having the diameter of 300 mm is mounted on
the suction holding stage 35, a sealed space is formed on the
suction holding stage 35 by the semiconductor wafer 5 and the
respective banks 42, 43 and 46. The sealed space has a negative
pressure by the suction operation of the suction apparatus. As a
result, the semiconductor wafer 5 is assuredly fully sucked and
held on the suction holding stage 35. The semiconductor wafer 5 is
horizontally held by the respective banks 42, 43 and 46 and many
pins 45.
At the time of inspection of the semiconductor wafer 5, when the
semiconductor wafer 5 having the diameter of 200 mm is mounted on
the suction holding stage 35, a sealed space is formed on the
suction holding stage 35 by the semiconductor wafer 5, the bank 43
and the convex portion 46. The sealed space has a negative pressure
by the suction operation of the suction apparatus. As a result, the
semiconductor wafer 5 is assuredly fully sucked and held on the
suction holding stage 35. The semiconductor wafer 35 is
horizontally held by the bank 43, the convex portion 46 and many
pins 45.
A notch portion 47 is formed at an outer peripheral part of the
suction holding stage 35. The notch portion 47 is formed in order
to detect a wafer edge of the semiconductor wafer 5 having the
diameter of 300 mm.
A hole 48 is formed at a position on the suction holding stage 35
which corresponds to a wafer edge position of the semiconductor
wafer 5. The hole 48 is formed in order to detect a wafer edge of
the semiconductor wafer 5 having the diameter of 200 mm.
The notch portion 47 and the hole 48 are formed in the radial
direction of the rotary stage 34 and the suction holding stage 35.
It is to be noted that respective banks 49 and 50 are formed on the
outer peripheries of the notch portion 47 and the hole 48. The
respective banks 49 and 50 are formed to have the same height as
another bank, e.g., the bank 43.
A sensor 51 is provided at an alignment position on the inspection
apparatus 2 as shown in FIGS. 2 and 3. The sensor 51 fixes a light
projecting element 52 and a light receiving element 53 so as to be
opposed to each other. The light projecting element 52 projects,
e.g., a fixed quantity of light 52a. The light projecting element
52 is, e.g., a light emitting diode. The light receiving element 53
outputs a detection signal corresponding to a light quantity which
is projected from the light projecting element 52 and incident
thereupon without being blocked by the wafer edge of the
semiconductor wafer 5. The light receiving element 53 is, e.g., a
photodiode.
In FIG. 2, the semiconductor wafer 5 having the diameter of 300 mm
is sucked on the rotary stage 34. When aligning the semiconductor
wafer 5, the rotary stage 34 moves up by a predetermined distance
above the height position of the suction holding stage 35. The
notch portion 47 is positioned in a detection area of the light
projecting element 52 and the light receiving element 53 by
movement of the X axis stage 31 and the Y axis stage 32 in the
direction of the axis XY. The detection area of the light
projecting element 52 and the light receiving element 53 is a
passage area of the light 52a projected from the light projecting
element 52.
In FIG. 3, the semiconductor wafer 5 having the diameter of 200 mm
is sucked on the rotary stage 34. When aligning the semiconductor
wafer 5, the rotary stage 34 moves up by a predetermined distance
above the height position of the suction holding stage 35. The hole
48 is positioned in the detection area of the light projecting
element 52 and the light receiving element 53 by movement of the X
axis stage 31 and the Y axis stage 32 in the direction of the axis
XY.
FIG. 5 shows an example of a detection signal outputted from the
sensor 51. The detection signal indicates a signal level change
corresponding to a light quantity which has entered the light
receiving element 53 without being blocked by the wafer edge of the
semiconductor wafer 5 in the light 52a projected from the light
projecting element 52.
The signal level change will now be described. It is often the case
that the semiconductor wafer 5 sucked on the rotary stage 34
deviates from a reference position of alignment. The reference
position of alignment is based on a central position of the rotary
stage 34, semiconductor wafer 5 and a direction of the notch (or an
original flat). When the semiconductor wafer 5 deviates from the
reference position of alignment and rotates in this state, the
semiconductor wafer 5 rotates in the eccentric state.
Then, in the detection area of the light projecting element 52 and
the light receiving element 53, a wafer edge position of the
semiconductor wafer 5 oscillates in accordance with a quantity of
eccentricity of the semiconductor wafer 5. As a result, a quantity
of the incident light on the light receiving element 53 varies. It
is to be noted that the quantity of the incident light upon the
light receiving element 53 is increased and a signal level of the
detection signal becomes high in the notch part of the
semiconductor wafer 5.
An alignment control portion 54 receives the detection signal
outputted from the sensor 51, and obtains positional information of
the wafer edge of the semiconductor wafer 5 based on the signal
level of the detection signal and a rotation angle of the rotary
stage 34. The wafer edge positional information is based on a
central position of the semiconductor wafer 5 and the direction of
the notch.
The alignment control portion 54 compares an alignment reference
position of the semiconductor wafer 5 and the wafer edge positional
information, and calculates a displacement of the semiconductor
wafer 5 relative to the alignment reference position in units of,
e.g., mm in the direction X and mm in the direction Y. The
alignment reference position of the semiconductor wafer 5 is set in
the alignment control portion 54 by an operator.
The alignment control portion 54 controls to move the X axis stage
31 and the Y axis stage 32 of the XY.theta. stage 21 in the
directions of the axis X and the axis Y in accordance with
displacement data of the semiconductor wafer 5 relative to the
alignment reference position.
As shown in FIGS. 2 and 3, an inspection portion 60 is provided
above the XY.theta. stage 21. The inspection portion 60 has a
microscope 61. The microscope 61 has an object lens 62 and an
eyepiece 63. An image pickup apparatus such as a CCD can be
attached to the microscope 61. The image pickup apparatus picks up
an image of the semiconductor wafer 5 enlarged by the microscope
61. The enlarged image of the semiconductor wafer 5 is displayed in
a monitor apparatus 64.
An operation portion 65 is provided on a front side F of the
inspection apparatus 2. The operation portion 65 effects an
operation to inspect the semiconductor wafer 5, an operation to
input an inspection result of the semiconductor wafer 5 and an
operation to input various kinds of data such as data concerning
the operation of the entire inspection apparatus 2.
The operation of the apparatus having the above-described structure
will now be described.
The carriage robot 4 extends the articulated arms 6 to 8 and the
hand 9 in a direction indicated by an arrow C, sucks and holds the
uninspected semiconductor wafer 5 in the wafer carrier 3a, and
moves to and stops at the wafer delivery position P.sub.1 while
retracting the articulated arms 6 to 8 and the hand 9.
Then, the carriage robot 4 extends the articulated arms 6 to 8 and
the hand 9 in a direction indicated by an arrow D, and moves the
sucked and held semiconductor wafer 5 above the carriage arm
24.
Subsequently, the swiveling arm 20 integrally moves up the three
carriage arms 24 to 26 by upward movement of the rotary shaft 23.
As a result, the carriage arm 24 receives the semiconductor wafer 5
held on the hand 9. At the same time, the carriage arm 24 sucks and
holds the semiconductor wafer 5 by start of suction of each suction
hole 27.
At this moment, if some semiconductor wafers 5 have been already
held on the swiveling arm 20, the carriage arm 25 receives the
macro inspected the semiconductor wafer 5.
At the micro inspection delivery position P.sub.3, the carriage arm
26 receives the micro inspected the semiconductor wafer 5. The
semiconductor wafer 5 is subjected to the micro inspection in the
inspection portion 60.
Then the swiveling arm 20 rotates around the rotary shaft 23 in the
counterclockwise direction (direction indicated by an arrow H) in
the drawing. The swiveling arm 20 moves down. As a result, the
carriage arm 24 moves to the macro inspection position P.sub.2. The
carriage arm 25 moves to the micro inspection delivery position
P.sub.3. The carriage arm 26 moves to the wafer delivery position
P.sub.1.
Description will now be given as to delivery of the semiconductor
wafer 5 at the micro inspection delivery position P.sub.3 and the
alignment operation of the semiconductor wafer 5.
The XY.theta. table 21 moves up the rotary stage 34 beyond the
height position of the suction holding stage 35.
Then, with the rotary stage 34 being moved up, the XY.theta. table
21 operates to move the X axis stage 31 and the Y axis stage 32,
moves the rotary stage 34 to the micro inspection delivery position
P.sub.3, and enters the standby mode.
The swiveling arm 20 causes the carriage arm 25 which holds the
semiconductor wafer 5 which has been already subjected to the macro
inspection to stop at the micro inspection delivery position
P.sub.3 by allowing circulation movement of the three carriage arms
24 to 26. As a result, the rotary stage 34 is positioned at the
delivery position (micro inspection delivery position P.sub.3) in
the substantial L shape of the carriage arm 26.
Thereafter, the swiveling arm 20 moves down the three carriage arms
24 to 26. As a result, the semiconductor wafer 5 on the carriage
arm 25 is delivered to the central part of the rotary stage 34. At
this moment, the suction operation of the carriage arm 25 is
canceled, and the suction operation of the rotary stage 34 is
started.
Then, with the rotary stage 34 which is sucking and holding the
semiconductor wafer 5 being moved up, the XY.theta. table 21
operates to move the X axis stage 31 and the Y axis stage 32. With
the movement, the XY.theta. table 21 moves the rotary stage 34
which is sucking and holding the semiconductor wafer 5 to the
alignment position.
At the alignment position, in case of the semiconductor wafer 5
having the diameter of 300 mm, the rotary stage 34 moves the notch
portion 47 to a position where it is matched with the optical axis
of the light projecting element 52 and the light receiving element
53 as shown in FIG. 2. The wafer edge of the semiconductor wafer 5
having the diameter of 300 mm is arranged on the optical axis of
the light projecting element 52 and the light receiving element 53
running through the notch portion 47.
When the rotary stage 34 rotates at a uniform velocity in this
arrangement state, the light 52a projected from the light
projecting element 52 is partially blocked by the wafer edge of the
rotating semiconductor wafer 5, and enters the light receiving
element 53 through the notch portion 47. As shown in FIG. 5, the
light receiving element 53 outputs a detection signal indicative of
a level change corresponding to a light reception quantity of the
received light 52a.
On the other hand, in case of the semiconductor wafer 5 having the
diameter of 200 mm, as shown in FIG. 3, the rotary stage 34 moves
the hole 48 to a position where it is matched with the optical axis
of the light projecting element 52 and the light receiving element
53. The wafer edge of the semiconductor wafer 5 having the diameter
of 200 mm is arranged on the optical axis of the light projecting
element 52 and the light receiving element 53 running through the
hole 48.
Thereafter, when the semiconductor wafer 5 rotates being eccentric
with respect to a predetermined posture like the above description,
the light receiving element 53 outputs a detection signal
indicative of a level change corresponding to a light reception
quantity of the received light 52a as shown in FIG. 5.
The alignment control portion 54 obtains a displacement of the
semiconductor wafer 5 with respect to the alignment reference
position based on the signal level of the detection signal
outputted from the sensor 51 and a rotation angle of the rotary
stage 34, and controls to move the XY.theta. stage 21 in accordance
with this displacement.
As a result, the semiconductor wafer 5 is positioned at the
alignment reference position.
Then, the rotary stage 34 which is sucking and holding the
semiconductor wafer 5 moves down beyond the height position of the
suction holding stage 35, and cancels the suction operation
relative to the semiconductor wafer 5.
At the same time, the suction holding stage 35 starts the suction
operation with respect to the semiconductor wafer 5. As a result,
the semiconductor wafer 5 is entirely sucked on the suction holding
stage 35.
Then, the image pickup apparatus picks up an image of the
semiconductor wafer 5 enlarged through the microscope 61. The image
of the semiconductor wafer 5 is displayed in the monitor apparatus
64. As a result, the micro inspection of the semiconductor wafer 5
is effected. It is to be noted that focusing of the object lens 62
in the microscope 61 relative to the semiconductor wafer 5 is
adjusted by moving up and down the suction holding stage 35.
Upon completion of the micro inspection, the suction holding stage
35 stops the suction operation with respect to the semiconductor
wafer 5. At the same time, the rotary stage 34 moves up and starts
the suction operation, thereby sucking and holding the
semiconductor wafer 5.
Subsequently, the XY.theta. stage 21 operates to move the X axis
stage 31 and the Y axis stage 32, and moves the semiconductor wafer
5 to the micro inspection delivery position P.sub.3.
At this moment, the carriage arm 25 is below the height position of
the semiconductor wafer 5 on the rotary stage 34. The swiveling arm
20 moves up and mounts the semiconductor wafer 5 on the carriage
arm 25.
The swiveling arm 20 again allows circulation movement of the three
carriage arms 24 to 26 at the micro inspection delivery position
P.sub.3, the wafer delivery position P.sub.1 and the macro
inspection position P.sub.2.
As described above, according to the embodiment, since the
semiconductor wafer 5 does not have to be carried between the
pre-alignment apparatus and the inspection apparatus by the
carriage robot, the time to perform the micro inspection relative
to the semiconductor wafer 5 can be shortened by a time required
for the carriage. As a result, it is possible to satisfy a
reduction in a tact time in manufacture required in a manufacture
field of the semiconductor wafer 5 and a reduction in the defect
inspection time of the semiconductor wafer 5 involved by
manufacture.
Further, since the pre-alignment apparatus does not have to be
additionally provided, the wafer inspection apparatus can be
minimized by an amount corresponding to the space in which the
pre-alignment apparatus is provided.
Since the alignment of the semiconductor wafer 5 also functions as
the rotary stage 34 of the inspection apparatus 2, the micro
inspection relative to the semiconductor wafer 5 can be performed
in the inspection apparatus 2 immediately after the alignment.
Therefore, since it is not necessary to carry the semiconductor
wafer 5 after the alignment, the micro inspection can be effected
while keeping the posture of the highly accurately aligned
semiconductor wafer 5.
A plurality of the semiconductor wafers 5 are not positioned and
they are accommodated at different positions in the wafer carrier
3a. When the semiconductor wafers 5 taken out from the wafer
carrier 3a are circulated to the micro inspection delivery position
P.sub.3 by the respective carriage arms 24 to 26, the respective
semiconductor wafers 5 are displaced with respect to the alignment
reference position, and a displacement quantity becomes large.
In such a case, by enlarging the detection area of the light
projecting element 52 and the light receiving element 53 for the
wafer edge of the semiconductor wafer 5, the sensor 51 can detect
the oscillation of the wafer edge of the semiconductor wafer 5 even
if a displacement quantity of the semiconductor wafer 5 is large.
As a result, it is possible to accurately obtain a deviation of the
semiconductor wafer 5 from the alignment reference position and a
deviation in the direction of the notch. Consequently, the
semiconductor wafer 5 can be highly accurately aligned.
If a displacement quantity of the semiconductor wafer 5 is large,
there is a method by which the semiconductor wafer 5 is pre-aligned
by the carriage robot 4 or the swiveling arm 20 and then delivered
to the rotary stage 34, for example. Even if this method is not
adopted, enlarging the detection area of the light projecting
element 52 and the light receiving element 53 enables alignment of
the semiconductor wafer 5 without performing pre-alignment.
Since the swiveling arm 20 circulates the three carriage arms 24 to
26 to the wafer delivery position P.sub.1, the macro inspection
position P.sub.2 and the micro inspection delivery position
P.sub.3, it can be caused to function as a buffer holding portion
which holds one semiconductor wafer 5 on the upstream side of
circulation from the inspection apparatus 2. As a result, upon
completion of the micro inspection relative to the semiconductor
wafer 5, the inspection apparatus 2 can immediately receive the
next semiconductor wafer 5 from one carriage arm 24, 25 or 26,
thereby reducing the time interval of the micro inspection for each
semiconductor wafer 5.
The swiveling arm 20 not only performs buffer holding of a
plurality of the semiconductor wafers 5, but it can sequentially
carry out the macro inspection for each semiconductor wafer 5 at
the macro inspection position P.sub.2 before the micro
inspection.
Since the notch portion 47 and the hole 48 are formed to the
suction holding stage 35, it is possible to cope with alignment of
the respective semiconductor wafers 5 having the diameter of 300 mm
and the diameter of 200 mm. It is to be noted that forming a
plurality of the holes 48 enables alignment of the semiconductor
wafers 5 having a plurality of diameter sizes.
It is to be noted that the present invention is not restricted to
the above-described embodiment, and various modifications can be
carried out without departing from the scope of the invention on an
embodying stage.
For example, as shown in FIG. 6, a notch portion 60 and a hole 61
are formed at opposed positions through the center of the holding
stage 33 from the notch portion 47 and the hole 48. A sensor 51
which detects the wafer edge of the semiconductor wafer 5 is
additionally provided to the notch portion 60 and the hole 61.
If a pair of the sensors 51 are provided, it is good enough to
rotate the rotary stage 34 at 180 degrees at the time of alignment.
As a result, the inspection time of the semiconductor wafer 5 can
be further reduced. Incidentally, if not only a pair but a
plurality of the sensors 51 are provided, a rotation angle of the
rotary stage 34 in alignment can be reduced, thus further
shortening the inspection time of the semiconductor wafer 5.
The sensor 51 may be constituted by a combination of a light source
which emits a slit light beam and a line sensor. In this case, the
slit light beam is emitted in a direction vertical to the wafer
edge of the semiconductor wafer 5. The line sensor detects a change
in an incident position of the slit light beam corresponding to a
wafer edge position which oscillates due to the eccentricity of the
semiconductor wafer 5. The alignment control portion 54 receives a
detection signal corresponding to the incident position of the slit
light outputted from the sensor 51, and calculates and obtains a
deviation of a central position of the semiconductor wafer 5 from
the alignment reference position and a deviation in the direction
of the notch or the original flat based on this detection signal
and the rotation angle of the rotary stage 34.
The sensor 51 may be of a reflection type which projects the light
onto the wafer edge of the semiconductor wafer 5 and receives the
reflected light from the wafer edge.
The sensor 51 may be attached anywhere within a substrate movement
range E. It is good to set an attachment position of the sensor 51
in such a manner that a distance from the alignment position to the
micro inspection position becomes minimum in the inspection
apparatus 2.
Furthermore, the attachment position of the sensor 51 may be
provided on the Y axis stage 32. In this case, the rotary stage 34
is rotated while moving the semiconductor wafer 5 is moved from the
macro inspection position P.sub.2 to the inspection apparatus 2 by
movement of the Y axis stage 32. In this period, the positional
information of the wafer edge position of the semiconductor wafer 5
can be obtained. The inspection time of the semiconductor wafer 5
can be further reduced.
The swiveling arm 20 may be constituted by two carriage arms.
The swiveling arm 20 may be eliminated, and the semiconductor wafer
5 may be directly delivered onto the rotary stage 34 from the
carriage robot 4. In this case, if, e.g., an L-shaped or U-shaped
hand 9 of the carriage robot 4 is used, the semiconductor wafer 5
can be delivered to/from the rotary stage 34.
Directly delivering the semiconductor wafer 5 onto the rotary stage
34 can reduce the movement distance of the XY.theta. stage 21,
thereby shortening the inspection time of the semiconductor wafer 5
by this reduced distance.
The holding stage 33 may be constituted by only the rotary stage
34. In this case, the rotary stage 34 having, e.g., .phi.80 mm is
used. The sensor 51 may be attached anywhere within the substrate
movement range E. If the semiconductor wafer 5 has, e.g., the
diameter of 300 mm or the diameter of 200 mm, it is good enough to
move the rotary stage 34 and move the wafer edge of the
semiconductor wafer 5 to the detection area of the sensor 51.
The apparatus according to the present invention can be applied for
alignment of the semiconductor wafer 5 in various kinds of
equipments such as a measuring apparatus which measures a line
width or the like of the semiconductor wafer 5, a pattern
inspection apparatus, a stepper and others. The apparatus according
to the present invention can be applied for alignment of various
kinds of objects as well as the semiconductor wafer 5.
* * * * *